Abstract:

Three methodologies are associated with production optimisation, namely, Theory of Constraints
(TOC), Lean and Six Sigma – and each boasts with a number of success stories. This dissertation
addresses the possibility of implementing all three these methodologies in a specific sequence at
an organisation and also sets out to determine the impact of this implementation.
A literature survey was conducted on all three stand-alone methodologies as well as on the
combined methodology, which is called the Theory of Constrains Lean Six Sigma (TLS). TLS
literature suggests that TOC should be implemented first with a view to identify the constraint in
an organisation. Lean implementation should follow in order to eliminate any waste in the
organisation. Lastly, Six Sigma should be implemented to optimise the process variability.
TOC literature explains that The Goal of any organisation is to make money. All other objectives
are only the means of achieving The Goal. The literature further indicates that the constraint in
any organisation determines the drumbeat, and that this constraint should be managed by means
of the Drum-Buffer-Rope methodology.
Lean literature points towards 14 Management Principles by means of which an organisation
should be managed in order to become a Lean organisation, while Six Sigma literature is
concerned with the DMAIC (Define-Measure-Analyse-Improve-Control) methodology used for
improvement projects and the belt system that is used to manage these improvement projects.
Jonker Sailplanes, a sailplanes manufacturer in Potchefstroom, South Africa, was used as a case
study for the implementation of TLS. A description is given of the processes and procedures that
were followed before and after the implementation of TLS. The TLS methodology had to be adapted in order to meet the specific needs of Jonker Sailplanes
into an adapted 14-step TLS implementation plan. After implementing TOC and Lean at Jonker
Sailplanes, it was found that the organisation was not ready for the transition from Lean projects
to Six Sigma projects. The implementation of Six Sigma was therefore referred for future
research.
One of the most significant findings of the current study was the very positive impact that the
implementation of TLS had on the organisation: the production tempo (throughput) of the
organisation has increased while the operating expenses per aircraft have decreased. This
confirms that the profit per aircraft has increased. A critical evaluation of the implementation of
the TLS methodology can therefore maintain that the implementation of TLS at Jonker Sailplanes
was a success since the production tempo (throughput) and the organisational profit were
increased and the implementation of the methodology was done with relative ease.
In terms of interpreting results it was also necessary to set out how Jonker Sailplanes proceeded
from a prototyping environment to a production setup, and how specifically identifying the
constraint helped to achieve this transition. Furthermore, is it argued that when Lean is
implemented before TOC, this could move the organisation away from The Goal, which is to make
money. The interpretation of findings suggests that the procedure followed at Jonker Sailplanes
was the most appropriate one.
Finally, recommendations are made for future studies in terms of how to further improve the
impact of the TLS implementation at Jonker Sailplanes.